Name: how enzymes adjust to their substrates
Uploaded: 2019-03-11T09:21:10.000Z
Duration: 1 min 13 s
Channel: JoVE

- [Anlatıcı] Genellikle protein olan enzimler üzerinde hareket edebilecekleri ve özgüllükleri olan moleküller olan subtratlara bağlanarak çalışırlar.
 Bu özellik temel olarak aktif oldukları bölgelerinin şekli ve kimyasal karakteristikleri ile alt maddeye bağlanan enzimin bölgesi tarafından belirlenir.
 Enzim aktivitesinin kilit anahtar modeliyle uyumlu olarak, bu bağlanma hem enzim hem de subtratın yapı ve şeklini değiştirir.
Bu, subtratı, reaksiyonun gerçekleşmesi için gereken daha yüksek enerji geçiş durumuna yaklaştırır.
 Örneğin, bağlarını zayıflatarak daha kolay tepki verebilmelerini sağlar.
 Reaksiyonun ürünü üretildikten sonra, enzim serbest bırakılır ve reaksiyonları bir kez daha katalize etmek için kullanılabilir.

İndüklenmiş uyum modeli

Induced-fit Model

Hücrelerdeki çoğu kimyasal reaksiyon, reaksiyonu tükenmeden veya kalıcı olarak değiştirilmeden hızlandıran enzimler ve biyolojik katalizörler gerektirir. Reaktiflerin ürünlere dönüştürülmesi için ihtiyaç duyulan aktivasyon enerjisini azaltarak çalışırlar. Genellikle protein olan enzimler, etki ettikleri bir substrat olan reaktant bir moleküle bağlanarak çalışırlar. 

<h4> Özgüllük </h4>

 Enzimler, substrat özgüllüğü sergiler, yani yalnızca belirli substratlara bağlanabilirler. Bu, esas olarak enzimin substrata bağlanan bölgesi olan aktif kısımlarının şekli ve kimyasal özellikleri tarafından belirlenir. 

 Uyarılmış enzim aktivitesi modeline göre, hem enzimin hem de substratın konformasyonunu veya şeklini değiştirir. Bu, substratı, örneğin daha kolay reaksiyona girebilmesi için bağlarını zayıflatarak reaksiyonun gerçekleşmesi için gereken daha yüksek enerji geçiş durumuna yaklaştırır. Enzimler ayrıca, reaksiyonun ilerlemesi için çevredeki hücresel ortama göre daha elverişli olan aktif kısım içinde koşullar yaratarak bir reaksiyonu hızlandırabilir. 

 Reaksiyonun ürünleri oluşturulduktan sonra, aktif bölgeden salınırlar ve enzim, reaksiyonları bir kez daha katalize etmek için kullanılabilir.

İndüklenmiş Uyum Modeli

Hücrelerdeki çoğu kimyasal reaksiyon, tüketilmeden veya kalıcı olarak değiştirilmeden reaksiyonu hızlandıran biyolojik katalizörler olan enzimlere ihtiyaç duyar. Onlar...

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JoVE Core

Biology

Biyoloji

Cellular Processes

Hücresel Süreçler

Metabolism

Metabolizma

KEY TERMS AND CONCEPTS

TEMEL TERİMLER VE KAVRAMLAR

how enzymes adjust to their substrates

Enzymes speed up many chemical reactions in cells. They are biological catalysts, so they increase reaction speed without being consumed or permanently changed. They do this by lowering the activation energy needed to turn reactants into products.

Enzymes are proteins that usually work by binding to a substrate, which is the reactant molecule they act on. They show substrate specificity, meaning they bind only certain substrates. This specificity depends mainly on the shape and chemical features of the enzyme’s active site, the region that binds the substrate.

The induced-fit model explains what happens after the substrate binds. The binding changes the enzyme’s shape, or conformation. This change helps bring the substrate closer to the higher-energy transition state needed for the reaction, such as by weakening bonds so the substrate can react more easily.

Enzymes can also make the active site a better place for the reaction than the surrounding cell environment. After the products form, they leave the active site. The enzyme can then catalyze the reaction again.

How Enzymes Adjust to Their Substrates

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induced-fit model

Enzymes speed up many chemical reactions in cells. They are biological catalysts, so they increase reaction speed without being consumed or permanently changed. They do this by lowering the activation energy needed to turn reactants into products. Enzymes are proteins that usually work by binding to a substrate, which is the reactant molecule they act on. They show substrate specificity, meaning they bind only certain substrates. This specificity depends mainly on the shape and chemical...

enzyme kinetics

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key terms and concepts

Learn how enzyme active sites change shape in the induced-fit model, helping substrates reach the transition state and reactions happen faster.

How Enzymes Adjust to Their Substrates | JoVE K12

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How Enzymes Adjust to Their Substrates

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